The time has come to pay attention to a symbolic supplement with which generations of trainees have literally grown up. We can consider BCAAs or branched-chain amino acids as gold-grade supplements because of their high research and generations of experience in their use. Moreover, they are present in our food anyway, even if we do not take them as a supplement.
Modern research sheds new light on their effectiveness. What turns out – dust in the eyes or justified fame? And is it true that they promote growth beyond hormonal stimulation? Are they safe? These and other questions are answered in the article in the most impartial way possible and with a scientific approach.
What are branched chain amino acids (BCAAs)?
With the abbreviations BCAA (branched-chain amino acid) and VRAK (branched-chain amino acids) we express the combination of three amino acids with a branched molecular structure. These are the amino acids leucine , isoleucine and valine.
Together with other 6 amino acids BCAAs belong to the group of essential ie. essential molecules for humans. It is interesting to know that nearly 35-40% of the composition of essential amino acids in the body and nearly 14-18% in muscle tissue are leucine, isoleucine and valine.
BCAAs are essential amino acids with a specific structure. They are obtained only from food and at the same time constitute a significant part of muscle tissue.
What is in the BCAA combination?
Each of the amino acids taken separately has common and unique functions, but their intake in combination creates a new type of effect. For now, the proportions of amino acid intake are thought to modify the effect by tilting it toward one function or another.
The ratio of leucine: isoleucine: valine varies in different formulas. There are different combinations:
- 2: 1: 1 – This is the oldest, researched and, one might say, established combination. The research around it is mainly for muscle protector.
- 4: 1: 1 – This is the second most widespread formula. The increased dose of leucine is to stimulate the mTOR signaling protein-enzyme responsible for encoding muscle growth and recovery, to reduce appetite and separately to stimulate insulininogenic action.
- 8: 1: 1 – A relatively new combination, focused mainly on the stimulation of mTOR and the idea that a whole bunch of anabolic and anti-catabolic hormones are stimulated along it .
- 100% leucine – an extremely popular option in recent years. The focus is only on leucine, because it is considered the only amino acid of the three with an anabolic effect. The benefits of pure leucine for gaining muscle mass are controversial at this stage, as leucine has been found to be far more effective in combination with essential amino acids.
- Combinations with non-integers – most often the ratio of amino acids in muscle tissue, in certain contractile proteins or the concentration of amino acids in cellular plasma at rest.
There is no data on whether a particular combination is better than another.
What you need to know about branched chain amino acids?
BCAA supplementation is considered an interesting nutrition strategy to improve the state of protein balance in skeletal muscle under a number of conditions. The most important are:
- muscle protective role – in heavy prolonged training by several mechanisms, in the absence of glycogen (either due to diet or exercise);
- stimulate muscle growth – in diets with excess calories thanks to mTOR, regardless of insulin levels (low carb diets);
- improve muscle performance and reduce fatigue (muscle and nerve) – including improve the work of creatine kinase, aldolase, myoglobin, reduce the strength of muscle cramps, improve concentration, functional strength.
However, not all claims have sufficient target-specific and well-controlled studies. For this purpose, below you will find the evidence for each effect separately.
BCAA stimulates protein synthesis in skeletal muscle cell cultures. Similarly, the stimulation of protein synthesis in skeletal muscle caused by the intake of a combined diet (proteins, fats , carbohydrates) is mainly due to BCAA in the diet.
One of the three amino acids, leucine, is a leading factor in the stimulation of protein synthesis under these conditions, thanks to its stimulating effect on the translation of ribosomal signal RNA into the ribosomes of muscle cells.
Recall – these are networks of cellular organelles that produce protein by attaching to mRNA (messenger RNA). A large number of synthesis mechanisms, including phosphorylation of ribosomal protein S6 Kinaza, eiF4E binding protein 1, eIF4G, contribute to the effect of leucine on initiating mRNA readings.
These mechanisms not only promote global protein synthesis (throughout the body) by initiating mRNA translation, but also contribute to deciding which protein to synthesize between competing mRNAs.
A key component in signal regulation is a protein kinase called the “mammalian target of rapamycin” or mTOR (the mammalian target of rapamycin).
The latter protein is known to promote the synthesis of muscle proteins in competition with the synthesis of other proteins in common synthesis centers (ribosomes), thanks to leucine.
All this means that, depending on the conditions of intake, chain-branched acids have a positive effect on muscle growth and recovery, including anabolic when eating a calorie excess.
When taken orally, BCAAs reach the muscles and organs through the blood and lymph and suppress proteolysis (breakdown of proteins) regardless of insulin levels , ie. act as a muscle protector without being dependent on insulin, which means that it can protect the muscles in the absence of carbohydrates or low blood sugar .
These are the conditions in the muscle cells and in the body during heavy long-term training, during glycogen depletion or during a diet low in carbohydrates (VPD, NVD, etc.).
Several other BCAA-related effects have been observed. First, it seems that their metabolism as a cellular fuel during oxidation in cells during exercise is associated with and activated along with that of fatty acids. The presence of BCAAs increases fat burning under these conditions (depleted glycogen).
In practice, BCAAs can be useful for increasing endurance, gaining lean muscle mass, or burning fat (preventing active weight).
What are they used for and what are the health benefits of BCAAs?
Although they have been used in sports nutrition and supplementation for over 50 years, BCAAs still need research to confirm their vitamin-like properties once and for all.
Below, the BB-Team has collected the most important of more than 30 studies conducted over the years on the effects of branched-chain amino acids.
Proven and potential benefits in humans:
- Reduce muscle damage and speed recovery in resistance trainees – results are achieved by taking BCAAs before and after exhaustion through falling jumps. The researchers suggest that this may be due to the high availability of BCAAs, which serve to improve protein synthesis and reduce secondary muscle damage associated with exercise. Similar results have been found in other earlier studies, with the final conclusion suggesting that muscle proteins are protected from catabolic processes during and after exercise. However, other studies have found no benefit in regulating muscle damage and reducing muscle fatigue.. In this case, it can be assumed that BCAAs either aid in some specific activities that exclude high-strength strength training, or BCAAs are more effective in some specific situations such as fasting training; (15, 22, 35)
- Improve the concentration of the mind during prolonged aerobic exercise (on average by + 20%). A number of cognitive benefits have been identified, such as improved response time, accuracy calculation, etc .. All of these benefits are associated with reduced fatigue during aerobic activities and are most significant in the final stages of training; (14, 37)
- Suppress general fatigueduring prolonged aerobic exercise – the effect is attributed to the ability of BCAAs to increase the flow of tryptophan to the brain receptor 5-HT (5-hydroxytryptamine). The results were measured after a 30-kilometer simulation of cross-country cycling, leading to a drop in glycogen levels, severe fatigue and exhaustion. However, it turns out that the effect of suppressing fatigue, in turn, is suppressed if exercisers take glucose during / after training. There is currently no information on what leads to a similar effect of suppressing the effectiveness of BCAAs. Increasing aerobic endurance and reducing fatigue during long aerobic activities is conditional. So far, there are strong opinions that this effect is optimal for beginners and intermediate athletes. The benefits of BCAAs in improving aerobic activity range from minimal to almost negligible in advanced athletes; (23, 36, 37). The anti-fatigue effect is significant in outdoor activities such as climbing, skiing, sailing and more. In this case, there are significant benefits from consuming high doses of BCAAs (40-50 g) for hours;
- Serve as muscle fuel during prolonged, depleting glycogen loads; (13, 30, 36, 37)
- Improve muscle recovery during long glycogen-depleting workouts – found in marathoners; (11, 30, 36, 37)
- Increase endurance and fat burning – with long glycogen-depleting workouts. This effect is due to the glycogen-saving properties of BCAAs, which stimulate fat oxidation; (30, 36, 37)
- Support liver health in patients with cirrhosis of the liver, hepatitis C – increased research confirming the benefits of including BCAAs in the treatment of patients. Reduce the risk of liver cancer in people with liver disease; (8-10, 28, 31)
- Improve appetite in cancer patients (+ 55% appetite, compared to 16% placebo); (5)
- Protect against loss of muscle strength and mass in people with amyotrophic lateral sclerosis (ALS) – there is evidence that they slow down the negative effect on the musculoskeletal system in Lou Gehrig’s syndrome. There are also studies that BCAAs can actually cause or worsen ALS. In this case, the dose and duration of administration should be taken into account. There are no definite conclusions so far; (6)
- Reduce creatinine synthesis when taken systemically before and after exercise. This is thought to be related to their involvement in cellular metabolism such as energy or protein synthesis. The survey is statistical, of medium scale. (16)
Unproven effects and evidence of no effect
- Leucine does not help with muscular dystrophy – at 0.2 g X kg, taken within a year; (7)
- They fail to elicit a hormonal response – at doses of 120 mg / kg, oral administration did not elicit a statistically different response in the bodies of the athletes performing them, performing series to failure with 80% 1PM. These include: insulin, cortisol , growth hormone , IGF-1; (17) Taking 1-5 g of BCAAs briefly increases blood insulin levels and affects the plasma concentration of free fatty acids. Statistically, however, this does not matter; (29)
- They fail to help increase the nitrogen balance in patients with injuries. (26)
- They affect the appetite, reduce it – for such an effect is theoretically believed to be responsible mTOR, which is increased by BCAA intake. However, there are no studies on whether and to what extent BCAA intake results in a similar decrease in appetite;
- Do not increase VO2 max . This is the degree of oxygen utilization during long-term aerobic activity; (32)
- They do not affect the formation of ketone bodies. This is true of the combination of the three amino acids, because valine and isoleucine block this property of leucine; (33)
- They do not cause secretion of neurotransmitters. This applies to dopamine , adrenaline and noradrenaline; (34)
- They do not affect lactic acid levels and muscle fatigue after strenuous physical activity. Most benefits in this direction are derived from practice. More observations are needed; (35)
- They do not directly affect insulin sensitivity, blood sugar or insulin. It is possible that isoleucine has independent benefits in this direction, which are suppressed by leucine. There is a study that indirectly identifies a potential deterioration in insulin sensitivity with long-term BCAA use. (38)
Do BCAAs really help in gaining muscle mass?
This is one of the main issues that are related to BCAAs. For years, they have been advertised as a dietary supplement to restore and increase muscle mass.
A brand new study from June 2017 looked in detail at the effects of BCAAs on myofibril muscle building and the overall effect of the three amino acids on strength athletes.
The results show a positive effect of branched chain amino acids, but it is extremely modest. The conclusion is that BCAAs alone are not very effective in building muscle mass and impact on strength training.
What does the study actually say?
BCAAs have little effect and activation of the mTOR mechanism is not sufficient in itself. The lack of other essential amino acids limits the positive effect of BCAAs. The same applies to leucine alone.
Taking EAA (essential amino acids) or whole protein can be just as effective or even more effective than taking BCAA alone. (39)
Other studies have reached similar conclusions. In a specific test, the addition of essential amino acids to a mix of protein and carbohydrates marked an increase in the insulin response. It has been found that this effect is stimulated not only by leucine but also by phenylalanine and tyrosine . An association between insulin secretion and plasma levels of these three amino acids has been established.
Studies of leucine have shown that it does not affect markers of anabolic processes in older men. Tests on essential amino acid complexes have found that they stimulate muscle anabolism in the elderly, with the balance of phenylalanine levels changing dramatically.
Scientific research suggests the benefits of EAA and whole protein over BCAAs when it comes to stimulating muscle metabolism.
Are there any side effects and contraindications to taking BCAAs?
- Potential toxicity to the central nervous system – do not exceed the recommended doses (times), do not combine with neurotoxins: glutamate , aspartame , D-aspartic acid, aspartate, monosodium glutamate. The neurotoxic effect was soon discussed in studies of professional footballers in Italy, in connection with an increased incidence of diseases of the nervous system. Studies with established toxicity are on mice and everything on the subject is at an early stage to draw firm conclusions. Overdose of BCAAs and susceptibility to such diseases are thought to lead to an increased risk; (27)
The most affected condition is amyotrophic lateral sclerosis (ALS or motor neurone disease). The main risk is associated with the stimulation of the mTOR mechanism, which stimulates the intoxication of motor neurons. One theory suggests that frequent ALS in athletes may be associated with increased BCAA supplementation.
- Indirect association with cerebral hyperammonemia – this is a condition that occurs in a liver problem with amino acid processing or sports with a huge volume and intensity(professional sport). This is the relatively new “science of ammonia fatigue” science. This is due to the fact that the amounts of ammonium products produced by the deamination of adenosine monophosphate (purine nucleotide cycle) and the oxidation of BCAAs cannot be fully detoxified by the liver. They saturate the blood and impair brain function, including damaging / killing cells. This is not directly related to BCAA intake, it happens without it – just taking BCAAs increases the potential to train even harder. i.e. the fault is not in them, but in the health risk approach to training. (12)
In 2012, a study was conducted on the toxicity of BCAA on the bodies of young athletes. The aim is to establish a tolerable upper limit. According to tests, the maximum allowable dose is 500 mg per kilogram of active weight. This is equal to 40 grams for an 80 kg man. Higher doses significantly increase serum ammonia levels. (31)
The safe limit for an 80 kg man is considered to be 40 grams of BCAA per day.